Method of manufacturing sputtering target assembly

Abstract

Described is a method of manufacturing a sputtering target assembly is that minimizes distortion during manufacture and a novel target assembly so produced. The method involves positioning a backing member in an external shoulder formed in the target member, electron beam welding mating surfaces and machining the interior surface of the welded assembly to provide a coextensive surface along the inner surfaces of the target and backing members. The resulting target assembly can withstand high water pressure and high sputter power levels.

We claim: 
     
       1. A method of manufacturing a sputtering target assembly having a target member and a backing member capable of producing an assembly wherein during manufacture distortion of the sputtering target assembly is not greater than about 0.003-inches in the lateral direction and not greater than about 0.005-inches in the transverse direction, comprising: providing a target member having an upper lateral target surface, a lower end and a side wall with an inner surface and an outer surface;   providing a backing member for the target member, said backing member having a top surface and a side wall with inner and outer surfaces, the top surface of the backing member being adapted to engage the lower end of the target member;   providing a shoulder in the outer surface of the side wall of the target member that extends inwardly and downwardly from the outer surface at the lower end of the target member and terminates in a lip, one side of the lip being at the inner surface;   positioning the top surface of the backing member within said shoulder of the target member so that said top surface is in surface-to-surface contact with the target member and the inner surface is in surface-to-surface contact with the lip, said side wall of said backing member being sized with respect to said shoulder so that the outer surface of the side wall of the backing member is substantially coextensive with the outer surface of the side wall of target member;   firmly holding the target and backing members together and electron beam welding the surface-to-surface contact areas of said target and backing members; and   machining the inner surface of the side wall of the backing member and the lip of the target member to remove the lip and provide a coextensive inner surface along the inner surfaces of the backing member and target member.   
     
     
       2. A method according to claim 1 further comprising machining the outer surface of the side walls of the target and backing member to provide a coextensive outer surface. 
     
     
       3. A method according to claim 1 wherein said target and backing member are firmly held together for electron beam welding by electron beam spot welding prior to final electron beam welding of the surface-to-surface contact areas. 
     
     
       4. A method according to claim 1 wherein said target and backing member comprise metals having the same major constituent. 
     
     
       5. A target assembly made according to the method of claim 4. 
     
     
       6. A method according to claim 1 wherein said target and backing members comprise material selected from the group consisting of aluminum and aluminum alloys, copper and copper alloys, and titanium and titanium alloys. 
     
     
       7. A method according to claim 1 wherein said target and backing members comprise a material from the group consisting of aluminum and aluminum alloys. 
     
     
       8. A target assembly made according to the method of claim 7 capable of withstanding water pressure of 60 psi and sputter power levels of greater than 12 kw. 
     
     
       9. A target assembly made according to the method of claim 1.